Stay-bolt for boilers.



E. I. DODDS.

STAY BOLT FOR BOILERS.

APPLICATION FILED OCT- 19.1914.

1 93,505 Patented Oct 31, 1916.

v6 INVENTOR UNETED STACEFiSLPATENT OFFICE.

ETHAN I. DODDS, 0F PITTSBURGH, PENNSYLVANIA, ASSIGNOB TO FLANNERY BOLT COMPANY, OF PITTSBURGH, PENNSYLVANIA.

STAY-BOLT FOR BOILERS.

Specification of'Letters Patent.

Application filed October 19, 1914.. Serial No. 867,413.

To all whom it may concern:

Be it known that I, ETHAN I. Donos, of Pittsburgh, in the county of Allegheny and State of Pennsylvania, have invented certain new and useful Improvements in Stay- Bolts for Boilers; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

My invention relates to an improvement in stay bolts for boilers, the object being to provide a bolt that will be free to yield and vibrate so as to accommodate itself to the lateral twisting or torsional movements of the boiler sheets, but be of suificient rigidity to prevent collapsing, buckling or spreading of the parts of the bolts while the latter is being applied to the boiler sheets, and it consists in the details of construction as will be more fully explained and pointed out in the claim. In the accompanying drawings, Figure l is a view of a blank from which the bolt is made; Fig. 2 shows the blank slotted centrally; Fig. 3 is a view in cross section of Fig. 2; Fig. 4 is a view of the blank after being compressed to close the slot; Fig. 5 is a view in cross section of Fig. 4; Fig. 6 is a view of the blank after it has been headed and twisted between the heads; Fig. 7 is a view in cross section of Fig. 6 and Fig. 8 is a view of the completed bolt.

Heretofore bolts designed to absorb the vibration and torsional movement of boiler sheets have been slotted longitudinally all the way through, and then twisted spirally and threaded, have been made of half round sections twisted and threaded. With such construction the bolts are structurally weak against compressive strains, are difiicult to properly thread, and will buckle in applying them to the boiler sheets, and particularly so if the threads bind.

In constructing my bolt I take a blank 1 of stay bolt iron, and punch therein a single slot 2, centrally throughout approximately the length of the shank of the bolt and in- Copies of this patent may be obtained for and in other instances they wardly past the center or neutral axis but not clear through the bolt. After the bolt has been slotted, the dilation at the sides caused by the slotting is reduced by dies or other tools, and the heads 8 are formed by dies or otherwise, after which the shank is twisted about 360, so that the single slot in the bolt forms a spiral around the shank between the heads 3. After the heads 3 and squared end 4: (for the wrench or other tool used in screwing the bolt to the boiler sheets) have been formed, the heads are threaded by cold or hot rolling or by dies and the tell tale 5 drilled into one head.

lVith this construction the shank is substantially rigid against longitudinal compressive strains encountered in applying the bolt, and sufficiently so against any torsional strains encountered in applying the bolt to the sheets. After the bolts have been applied they yield or give laterally so as to accommodate themselves to the vibrations of the boiler sheets and the bases of the slots, or the comparatively thin webs closing the slots at the bottom are designed to break away under continued vibration thus separating the shank into two parts connected by the heads only. This leaves the bolt in a condition to take care of expansive stresses on the sheets but comparatively free to move or give with the lateral movements of the sheets.

Having fully described my invention what I claim as new and desire to secure by Letters-Patent, is 2- V A stay bolt having a single slot extending spirally around the shank throughout the lengthof the latter and inwardly past the center of the bolt but not wholly through the same, the said slot extending approximately around the shank.

In testimony whereof, I have signed this specification in the presence of two subscribing witnesses.

ETHAN I. DODDS.

Washington, D. (3.. 

